Evaluation Method for Viscoelastic Damper subjected to Long-Duration Wind Loading by Equivalent Sinusoidal Waves

Abstract

Viscoelastic (VE) dampers are widely installed in tall buildings to mitigate structural vibrations induced by earthquake and strong wind. They dissipate the kinetic energy through shear deformation of the steel-sandwiched VE material, and in the process, heat is generated within the damper. Since the VE dampers properties (i.e., damping and stiffness) are temperature and frequency dependent, significant damper temperature increase from long-duration loading (e.g., wind loading) can greatly affect their performance. Customarily, their properties are easily evaluated from the hysteretic relationship of force and deformation obtained from harmonic loading. However, wind-induced vibrations of tall buildings are random by nature. Hence, the authors propose an evaluation method by considering equivalent sinusoidal waves of the long-duration random deformation based on the random vibration or spectral approach which is fundamentally used in wind engineering. Taking into account the frequency dependency of VE dampers, low-frequency and high-frequency components of the random deformation are separated, thus, two equivalent sinusoidal waves are considered in the dynamic analysis considering heat generation and transfer analysis. Combined results from these equivalent sinusoidal waves agree well those from the original random deformation.